Hilda Margaret Bruce (5 April 1903 – 2 November 1974) was a British

zoologist Zoology ( , ) is the scientific study of animals. Its studies include the structure, embryology, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Zoology is one ...

, best known for her discovery of the

Bruce effect The Bruce effect, or pregnancy block, is the tendency for female rodents to terminate their pregnancies following exposure to the scent of an unfamiliar male. The effect was first noted in 1959 by Hilda M. Bruce, and has primarily been studied ...

, a pheromonal behaviour observed in many

rodent Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and Mandible, lower jaws. About 40% of all mammal specie ...

species. Her work on the control of fertility earned her the Oliver Bird Medal.

Biography

Hilda Bruce was born on 5 April 1903. She was educated at

St Leonards School St Leonards School is a co-educational private boarding and day school for pupils aged 4–19 in St Andrews, Fife, Scotland. Founded in 1877 as St Andrews School for Girls Company, it adopted the St Leonards name upon moving to its current pre ...

. In 1923, she began her tertiary studies at

King's College for Women Kings or King's may refer to: *Kings: The sovereign heads of states and/or nations. *One of several works known as the "Book of Kings": **The Books of Kings part of the Bible, divided into two parts **The ''Shahnameh'', an 11th-century epic Persia ...

, where she received a BSc in Household and Social Science, and another in

Physiology Physiology (; ) is the science, scientific study of function (biology), functions and mechanism (biology), mechanisms in a life, living system. As a branches of science, subdiscipline of biology, physiology focuses on how organisms, organ syst ...

. In 1928, Bruce joined the

National Institute for Medical Research The National Institute for Medical Research (NIMR), was a medical research institute based in Mill Hill, on the outskirts of north London, England. It was funded by the Medical Research Council (MRC); In 2016, the NIMR became part of the new F ...

(NIMR) at Mount Vernon, Hampstead. Her early research was dedicated towards the understanding of

Vitamin D Vitamin D is a group of structurally related, fat-soluble compounds responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, along with numerous other biological functions. In humans, the most important compo ...

; she also jointly published the first article describing the breeding characteristics of the

golden hamster The golden hamster or Syrian hamster (''Mesocricetus auratus'') is a rodent belonging to the hamster subfamily, Cricetinae. Their natural geographical range is in an Arid, arid region of northern Syria and southern Turkey. Their numbers have be ...

. In 1933, Bruce was employed by the

Pharmaceutical Society The Royal Pharmaceutical Society (RPharmS or RPS) is the body responsible for the leadership and support of the pharmacy profession (pharmacists) within England, Scotland, and Wales. It was created along with the General Pharmaceutical Council ...

, where she continued her research on Vitamin D. In 1941, she was appointed to set up the Cod Liver Oil (Poultry) Standardisation Laboratory. In 1944, she returned to the NIMR, where she formulated specialised diets for

laboratory animal Animal testing, also known as animal experimentation, animal research, and ''in vivo'' testing, is the use of animals, as model organisms, in experiments that seek answers to scientific and medical questions. This approach can be contrasted ...

s. From the early 1950s, Bruce turned her attentions towards

sexual behaviour Human sexual activity, human sexual practice or human sexual behaviour is the manner in which humans experience and express their sexuality. People engage in a variety of sexual acts, ranging from activities done alone (e.g., masturbation) t ...

rodents Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia ( ), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are n ...

, particularly the

Whitten effect The Whitten effect is stimulation, by male pheromones, of synchronous estrus in a female population. Social signals, or social stimuli, have an effect on reproduction in all mammals. For certain female mice, the pheromones contained in the urin ...

. In 1959, she published her discovery of what is now called the

, the

termination of pregnancy Abortion is the early termination of a pregnancy by removal or expulsion of an embryo or fetus. Abortions that occur without intervention are known as miscarriages or "spontaneous abortions", and occur in roughly 30–40% of all pregnanci ...

following exposure to the scent of an unfamiliar male. Bruce retired from the NIMR in 1963, but continued part-time research, variously on

nutrients A nutrient is a substance used by an organism to survive, grow and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...

development Development or developing may refer to: Arts *Development (music), the process by which thematic material is reshaped * Photographic development *Filmmaking, development phase, including finance and budgeting * Development hell, when a proje ...

and

pheromones A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavi ...

, at the Department of Investigative Medicine in

Cambridge Cambridge ( ) is a List of cities in the United Kingdom, city and non-metropolitan district in the county of Cambridgeshire, England. It is the county town of Cambridgeshire and is located on the River Cam, north of London. As of the 2021 Unit ...

. She continued work at the Department until 1973. In her later years, Bruce largely used a wheelchair, having been afflicted with worsening

rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects synovial joint, joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and h ...

since 1942.

Bruce effect

Throughout the 1950s, Bruce studied

in laboratory mice, with a particular interest in oestrus synchronisation. In one experiment, she housed newly mated pregnant females with male mice that were not the father of the carried embryo. As a result, the rate of

miscarriage Miscarriage, also known in medical terms as a spontaneous abortion, is an end to pregnancy resulting in the loss and expulsion of an embryo or fetus from the womb before it can fetal viability, survive independently. Miscarriage before 6 weeks ...

s increased, these females subsequently returning to

oestrus The estrous cycle (, originally ) is a set of recurring physiological changes induced by reproductive hormones in females of mammalian subclass Theria. Estrous cycles start after sexual maturity in females and are interrupted by anestrous phas ...

and mating with the new male. No increased rate of miscarriages occurred when pregnant mice were paired with juvenile or

castrated Castration is any action, surgical, chemical, or otherwise, by which a male loses use of the testicles: the male gonad. Surgical castration is bilateral orchiectomy (excision of both testicles), while chemical castration uses pharmaceutical ...

mice. Her colleague Alan Parkes, who had recruited her to the NIMR in 1944, helped her to pursue the initial findings that eventually lead to this discovery.

The National Institute for Medical Research

Following the isolation of pure vitamin D in 1931, Bruce worked in collaboration with Askew, Philpot and Webster in the Department of Biological Standards, determining the stability of the pure substance. At this time, Bruce was also working with Dr Callow in the Department of Physiology, Pharmacology and Biochemistry, determining the healing effect of vitamin D in rats with rickets.

Publications

* * * * *

References

{{DEFAULTSORT:Bruce, Hilda British mammalogists English zoologists 1903 births 1974 deaths Women mammalogists British women zoologists National Institute for Medical Research faculty Alumni of King's College London People educated at St Leonards School 20th-century Argentine people 20th-century British zoologists 20th-century British women scientists